DKK2 Impairs Tumor Immunity Infiltration and Correlates with Poor Prognosis in Pancreatic Ductal Adenocarcinoma

DKK2 promotes the progression of oral squamous cell carcinoma through the PI3K/AKT signaling pathway

OBJECTIVE

This study aimed to investigate the impact of Dickkopf 2 (DKK2) on the progression of oral squamous cell carcinoma (OSCC) and explore its role in the PI3K/AKT signaling transduction pathway.

MATERIALS AND METHODS

The study initially examined the expression of the DKK2 gene in OSCC tissues and normal tissues. Simultaneously, the expression of DKK2 in HOK cells and OSCC cells was verified, and changes in DKK2 expression under hypoxic conditions were detected. DKK2 overexpression and knockdown were performed in SCC-15 and CAL-27 cells. Subsequently, the effects of DKK2 on the proliferation, migration and invasion of OSCC were detected. Western blotting was employed to detect the expression of key proteins in the DKK2/PI3K/AKT signaling axis before and after transfection, and further explore the relevant molecular mechanisms.

RESULTS

Compared to normal tissues, DKK2 expression was elevated in OSCC tissues. The expression of DKK2 in the SCC-15 and CAL-27 cell lines was higher than that in HOK cells, and hypoxic conditions could promote DKK2 expression. DKK2 overexpression promoted cell proliferation, migration, and invasion, while DKK2 knockdown inhibited these processes. DKK2 overexpression activated the PI3K/AKT pathway, while DKK2 knockdown suppressed this pathway.

CONCLUSION

This study suggests that hypoxic conditions enhance the expression of DKK2 in OSCC. DKK2 regulates the proliferation, migration, and invasion of OSCC through the PI3K/AKT signaling pathway.

The assessment of Dickkopf-1 and Dickkopf-2 protein concentration in different subtypes of non-small cell lung cancer subtypes

Introduction

Lung cancer is one of the most prevalent cancers worldwide. Dickkopf-1 (DKK-1) and -2 (DKK-2) are important proteins for the regulated Wnt signalling pathway. Alternations in the Wnt pathway are associated with tumour progression. The aim of the study was to analyse the concentration of DKK-1 and DKK-2 in tumour and matched non-tumour (NT) samples of 65 patients with non-small cell lung cancer (NSCLC), including 3 subtypes: adenocarcinoma (AC), squamous cell carcinoma (SCC), and large cell carcinoma (LCC).

Material and methods

The protein concentration was measured by enzyme-linked immunosorbent assay (ELISA) in homogenates.

Results

The difference between the level of DKK-1 in tumour and NT specimens was not significant for the whole NSCLC group and SCC and LCC subtype, while in AC samples they were significantly higher (p = 0.028). The highest concentration of DKK-1 was found in the advanced NSCLC samples, with the T4 parameter as well as stage III. Significantly decreased DKK-2 concentrations were detected in all NSCLC subtypes (p < 0.05). Moreover, the DKK-2 level was higher in non-smokers than in smokers. The results indicate that concentrations of DKKs were different in relation to subtypes as well as clinical and socio-demographic parameters. The concentration of DKKs could be associated with the progression of NSCLC.

Conclusions

We suggest that DKK-1 could play an oncogenic role in AC, while DKK-2 could be a tumour suppressor in all NSCLC subtypes. Dickkopf-1 and DKK-2 proteins could have differential roles in the Wnt signalling pathway, which is important in many cellular processes, such as proliferation and apoptosis.

Boosting the therapeutic potential of cell secretome against osteoarthritis: Comparison of cytokine-based priming strategies

The secretome, or conditioned medium (CM), from Mesenchymal Stem/stromal Cells (MSCs) has recently emerged as a promising cell-free therapeutic against osteoarthritis (OA), capable of promoting cartilage regeneration and immunoregulation. Priming MSCs with 10 ng/ml tumor necrosis factor α (TNFα) and/or 10 ng/ml interleukin 1β (IL-1β) aims at mimicking the pathological milieu of OA joints in order to target their secretion towards a pathology-tailored phenotype. Here we compare the composition of the CM obtained after 24 or 72 h from untreated and cytokine-treated adipose-derived MSCs (ASCs). The 72-hour double-primed CM presents a higher total protein yield, a larger number of extracellular vesicles, and a greater concentration of bioactive lipids, in particular sphingolipids, fatty acids, and eicosanoids. Moreover, the levels of several factors involved in immunomodulation and regeneration, such as TGF-β1, PGE2, and CCL-2, are strongly upregulated. Additionally, the differential profiling of 80 bioactive molecules indicates that primed CM is enriched in immune cell chemotaxis and migration factors. Our results indicate that pre-conditioning ASCs with inflammatory cytokines can modulate the composition of their CM, promoting the release of factors with recognized anti-inflammatory, chondroprotective, and immunoregulatory properties.

Identification of a novel immune checkpoint molecule V-set immunoglobulin domain-containing 4 that leads to impaired immunity infiltration in pancreatic ductal adenocarcinoma

BACKGROUND

Checkpoint-based immunotherapy has failed to elicit responses in the majority of patients with pancreatic cancer. In our study, we aimed to identify the role of a novel immune checkpoint molecule V-set Ig domain-containing 4 (VSIG4) in pancreatic ductal adenocarcinoma (PDAC).

METHODS

Online datasets and tissue microarray (TMA) were utilized to analyze the expression level of VSIG4 and its correlation with clinical parameters in PDAC. CCK8, transwell assay and wound healing assay were applied to explore the function of VSIG4 in vitro. Subcutaneous, orthotopic xenograft and liver metastasis model was established to explore the function of VSIG4 in vivo. TMA analysis and chemotaxis assay were conducted to uncover the effect of VSIG4 on immune infiltration. Histone acetyltransferase (HAT) inhibitors and si-RNA were applied to investigate factors that regulate the expression of VSIG4.

RESULTS

Both mRNA and protein levels of VSIG4 were higher in PDAC than normal pancreas in TCGA, GEO, HPA datasets and our TMA. VSIG4 showed positive correlations with tumor size, T classification and liver metastasis. Patients with higher VSIG4 expression were related to poorer prognosis. VSIG4 knockdown impaired the proliferation and migration ability of pancreatic cancer cells both in vitro and in vivo. Bioinformatics study showed positive correlation between VSIG4 and infiltration of neutrophil and tumor-associated macrophages (TAMs) in PDAC, and it inhibited the secretion of cytokines. According to our TMA panel, high expression of VSIG4 was correlated with fewer infiltration of CD8⁺ T cells. Chemotaxis assay also showed knockdown of VSIG4 increased the recruitment of total T cells and CD8⁺ T cells. HAT inhibitors and knockdown of STAT1 led to decreased expression of VSIG4.

CONCLUSIONS

Our data indicate that VSIG4 contributes to cell proliferation, migration and resistance to immune attack, thus identified as a promising target for PDAC treatment with good prognostic value.

Dickkopf proteins in pathological inflammatory diseases

The human body encounters various challenges. Tissue repair and regeneration processes are augmented after tissue injury to reinstate tissue homeostasis. The Wnt pathway plays a crucial role in tissue repair since it induces target genes required for cell proliferation and differentiation. Since tissue injury causes inflammatory immune responses, it has become increasingly clear that the Wnt ligands can function as immunomodulators while critical for tissue homeostasis. The Wnt pathway and Wnt ligands have been studied extensively in cancer biology and developmental biology. While the Wnt ligands are being studied actively, how the Wnt antagonists and their regulatory mechanisms can modulate immune responses during chronic pathological inflammation remain elusive. This review summarizes DKK family proteins as immunomodulators, aiming to provide an overarching picture for tissue injury and repair. To this end, we first review the Wnt pathway components and DKK family proteins. Next, we will review DKK family proteins (DKK1, 2, and 3) as a new class of immunomodulatory protein in cancer and other chronic inflammatory diseases. Taken together, DKK family proteins and their immunomodulatory functions in chronic inflammatory disorders provide novel insights to understand immune diseases and make them attractive molecular targets for therapeutic intervention.

Dickkopf signaling, beyond Wnt-mediated biology

Dickkopf1 (DKK1) was originally identified as a secreted protein that antagonizes Wnt signaling. Although DKK1 is essential for the developmental process, its functions in postnatal and adult life are unclear. However, evidence is accumulating that DKK1 is involved in tumorigenesis in a manner unrelated to Wnt signaling. In addition, recent studies have revealed that DKK1 may control immune reactions, although the relationship of this to Wnt signaling is unknown. Other DKK family members, DKK2-4, are likely to have their own functions. Here, we review the possible novel functions of DKKs. We summarize the characteristics of receptors of DKKs and the signaling mechanisms through DKKs and their receptors, provide evidence showing that DKKs are involved in tumor aggressiveness independently of Wnt signaling, and emphasize promising cancer therapies targeting DKKs and receptors. Lastly, we discuss various physiological and pathological processes controlled by DKKs.

A prognostic score based on long-term survivor unique transcriptomic signatures predicts patient survival in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is known for its poor prognosis with few long-term survivors. This study aimed to establish a prognostic score using unique transcriptomic profiles of long-term survivors to be used as a patient selection tool for meaningful clinical intervention in PDAC. In TCGA PDAC cohort, 16 genes were significantly upregulated in the long-term survivor tumors. A prognostic score was established using these 16 genes by LASSO Cox regression, and PHKG1, HOXA4, ISL2, DMRT3 and TRA2A gene expressions were included in the score. The prognostic value was confirmed in both testing and validation cohorts. The characteristics of the high score tumor was investigated by bioinformatical approach. The high score tumor was associated with TP53 mutation but not with other commonly enhanced signaling pathways in PDAC. The high score tumor was associated with higher tumor mutational burden and unfavorable tumor microenvironment (TME), such as lower infiltration of CD8-positive T cells and dendritic cells, and less cell composition of mature blood vessels and fibroblasts. The high score tumor was also associated with enhanced cell proliferation and margin positivity after surgery. The impact of score component genes on the cell proliferation was investigated by in vitro experiments. Silencing of the score component genes promoted cell proliferation. In conclusion, the prognostic score predicted PDAC patient survival and was associated with cancer aggressiveness such as unfavorable TME and enhanced cell proliferation.

CircCNIH4 inhibits gastric cancer progression via regulating DKK2 and FRZB expression and Wnt/β-catenin pathway

Background

Circular RNAs (circRNAs) have been reported to play an important role in tumor progression in various cancer types, including gastric cancer. The aim of this study was to investigate the role of circCNIH4 (hsa_circ_0000190) in gastric cancer and the underlying mechanism.

Methods

The expression levels of circCNIH4 and Wnt antagonist genes were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of β-catenin, Ki67, Dickkopf 2 (DKK2) and Frizzled related protein (FRZB) were measured by western blot. Ectopic overexpression or knockdown of circCNIH4, proliferation, apoptosis, migration and invasion by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry and transwell assay in vitro, and in vivo experiment, were employed to assess the role of circCNIH4 in gastric cancer.

Results

CircCNIH4 was downregulated in gastric cancer tissues and cells. Overexpression of circCNIH4 inhibited gastric cancer cell proliferation, migration and invasion and promoted apoptosis by inactivating Wnt/β-catenin pathway in vitro. CircCNIH4 induced the expression of DKK2 and FRZB in gastric cancer cells. Moreover, silencing of DKK2 or FRZB reversed circCNIH4 overexpression-mediated effects on gastric cancer cells. Additionally, circCNIH4 suppressed tumor growth via regulating DKK2 and FRZB expression in gastric cancer in vivo.

Conclusion

Our study demonstrated that circCNIH4 played a tumor-inhibiting role through upregulating DKK2 and FRZB expression and suppressing Wnt/β-catenin pathway in gastric cancer, which might provide a potential biomarker for the diagnosis and treatment of gastric cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40709-021-00140-x.

Characterization of the Immune Cell Infiltration Profile in Pancreatic Carcinoma to Aid in Immunotherapy

The tumor microenvironment (TME) is comprised of tumor cells, infiltrating immune cells, and stroma. Multiple reports suggest that the immune cell infiltration (ICI) in TME is strongly associated with responsiveness to immunotherapy and prognosis of certain cancers. Thus far, the ICI profile of pancreatic carcinoma (PC) remains unclear. Here, we employed two algorithms to characterize the ICI profile of PC patients. Based on our results, we identified 2 ICI patterns and calculated the ICI score by using principal component analysis. Furthermore, we revealed that patients with low ICI scores had a better prognosis, compared to high ICI scores. Moreover, we discovered that a low tumor mutation burden (TMB) offered better overall survival (OS), relative to high TMB. In this study, a high ICI score referred to elevated PD-L1/TGF-β levels, increased activation of cell cycle pathway and DNA repair pathway, as well as reduced expression of immune-activation-related genes. We also demonstrated that three metabolic pathways were suppressed in the low ICI score group. These data may explain why a high ICI score equates to a poor prognosis. Based on our analysis, the ICI score can be used as an effective predictor of PC prognosis. Hence, establishing an ICI profile, based on a large patient population, will not only enhance our knowledge of TME but also aid in the development of immunotherapies specific to PC.

The Clinical Significance of Dickkopf Wnt Signaling Pathway Inhibitor Gene Family in Head and Neck Squamous Cell Carcinoma

BACKGROUND Dickkopf Wnt signaling pathway inhibitor (DKK) gene family, which is known to inhibit the Wnt regulation process, is widely found in cancers. However, the roles and functions of specific family members in head and neck squamous cell carcinoma (HNSCC) are still unclear. MATERIAL AND METHODS Online bioinformatics tools (Oncomine, UALCAN, Kaplan-Meier plotter, GEPIA, Metascape, and STRING) were used to analyze the relationships between distinct DKKs and HNSCC. The transcriptome expression, clinical association, functions, pathways, and protein-protein interaction networks of DKKs in HNSCC were explored. RESULTS The mRNA expression of DKK1, DKK3, and Dickkopf-like acrosomal protein 1 (DKKL1) in HNSCC was significantly higher than in normal tissues, while that of DKK4 was lower. The mRNA expression of DKK1, DKK3, and DKKL1 was elevated in higher-grade HNSCC. The mRNA expression of DKK1 and DKK3 was elevated in human papillomavirus (HPV)-negative HNSCC, while DKKL1 had a higher mRNA expression in HPV-positive HNSCC. In addition, DKK1 was significantly associated with unfavorable overall survival in HNSCC patients. DKK3 was more likely to be a negative factor for the 5-year survival rate, while DKK4 was the opposite. DKK1 function was mainly enriched in GTPase-mediated signal transduction. Porcupine O-acyltransferase, a key regulator of the Wnt signaling pathway, was also associated with DKK1 in the protein-protein interaction network. CONCLUSIONS With regard to improving the therapeutic strategies of HNSCC in the future, DKK1 could be an unfavorable prognostic biomarker. DKK3, DKK4, and DKKL1 might be potential biomarkers for HNSCC.